[lp4vn]

The article cleverly groups the budget in three categories:

- A first one that develops a product that creates a value for the company in the present(sales/marketing).

- A second one that develops a product that will possibly create value for the company in the future(research/development).

- And the last one that develops a product that created value for the company in the past and now has only to be maintained(maintenance).

Honestly I think that this division is a bit tautological. Everybody in the industry knows that maintenance project are bad and only are worth it if you're making a good money working in them. Now in practice the hypothetical division between sales/marketing and research/development that the author proposes is pretty blurry and in my opinion doesn't do a great service in categorizing the activity of a developer.